Internal combustion engine cylinder heads



April 6, 1965 H. A. WHITEHEAD 3,176,666

INTERNAL COMBUSTION ENGINE CYLINDER HEADS Filed Feb. 3, 1964 2 Sheets-Sheet 1 April 6, 1965 H. A. WHITEHEAD 3,176,666

INTERNAL COMBUSTION ENGINE CYLINDER HEADS Filed Feb. 3, 1964 2 Sheets-Sheet 2 United States Patent 3,176,666 INTERNAL COMBUSTION ENGINE CYLINDER HEADS Herbert A. Whitehead, Saddlewortlr, Waterloo Lane, Skeilingthorpe, Lincoln, England Filed Feb. 3, 1964, Ser. No. 341,985 9 Claims. (Cl. 12.3-41.82)

This invention relates to the design, and particularly the cooling, of liquid-cooled cylinder heads for overheadvalve internal-combustion engines.

The raising of the specific power of internal combustion "ice , tween liner and fire plate 14, and through all the engines by increasing power ratings has resulted in the subjection of the parts bounding the combustion space to severe thermal stresses, giving rise to undesirable effects such as crazy cracking and corrosion of the surface skin, thermal distortion and displacement of parts, cylinder head gasket failures, failure of valve seat sealing surfaces, and cracking in parts of unequal thickness. The worst effects are encountered in the hot wall or deck of the cylinder head separating the head from the combustion space, wherein inlet and exhaust valve ports and seats, injector or sparking plug holes, air starter holes, and the like, involve unequal thicknesses and openings in the material of the said deck, the resulting temperature distribution lending to high thermal stresses.

The invention provides an improved cylinder head with a separate fire plate, in which the coolant is enabled to flow closer to the hottest parts, and in which the coolant velocity and hence the heat transfer coefiicient can be closely controlled, reducing thermal stresses and distortion to negligible proportions and eliminating the need for non-rigid support of the fire plate periphery.

The following description relates to the accompanying drawings which show by way of example only, how the invention may be embodied in the cylinder head of a water-cooled compression-ignition overhead-valve engine with two air inlet and two exhaust poppet valves symmetrically disposed around a central fuel injector coaxial with the piston.

In the drawings:

FIGURE 1 is a vertical section through part of a cylinder head showing a fire plate and associated parts according to the invention; and

FIGURE 2 is a similar fragmentary section showing an alternative central fixing for the fire plate.

Referring to FIGURE 1, a cylinder head 11 has four valve ports of which two, 12, 13, are shown, and is provided with a separate, removable and replaceable steel fire plate 14, acting as the combustion space wall or deck K of the cylinder head. The fire plate 14 extends over and is coaxial with a wet cylinder liner 15 to which it transmits the cylinder head fastening load. Each of the four valve ports of which two, 12 and 13, are shown, is provided with a steel valve seat insert 16, 17 welded to the fire plate at 21 on its hot combustion space face 18 and at 20 on its cool opposite face 19. A fuel injector guide tube 22 is screwed at its bottom end 23 to the centre of the fire plate and at its top end (not shown) to the top deck of the cylinder head, the centre of the fire plate to a remote and therefore cool part of the cylinder head.

An inter-connected series of coolant fiow passages formed in the fire plate 14, between its hot face 18 and cool face 19 substantially wholly encircle each insert and the injector guide tube 22. The passage surrounding guide tube 22 is interconnected with all other passages and is also connected with an inlet into cylinder head 11. Each insert coolant flow passage is connected with two inlet ports positioned side by side in the periphery of the fire plate 14, and the flow from the two inlet ports is divided around the whole periphery of the insert. a (One inlet port plurality of inlet ports, in a generally radially inward direction through the interconnecting passages in the fire plate 14, to the guide tube 22, and from thence into the cylinder head 11. Of course the coolant flow may occur in the opposite sense, from an inlet into the cylinder head downward to the guide tube and in a generally radially outward direction through the interconnecting passages in the fire plate and through outlet ports at the periphery of the fire plate to the exterior of the cylinder liner. Water seals and gas seals are of course provided where necessary. No high-pressure combustion seals between the combustion face and the cylinder head are required, beyond those necessary for a conventional cylinder head.

The coolant circuit for the cylinder head and fire plate and parts secured thereto, the coolant flowing through said interconnecting passages including a passage surrounding a fuel injector or spark plug, may be separate from that for the cylinder.

FIGURE 2 shows a second embodiment of the invention wherein the centre of the fire plate is fixed to the cylinder head not by an injector guide tube, but by four through-bolts, of which two are shown, radially disposed around the injector. Through-bolts 33, 34 are attached to'fire plate 31 by hollow screwed studs 35, 36. In assembly, the studs 35, 36, are screwed into fire plate 31, and through-bolts 33, 34, are inserted through holes (not shown) in the upper deck or other remote, cool part of cylinder head 32, and screwed into the upper ends of studs 35, 36. Holes in studs 35, 36 and an annular passage 37 in fire plate 31 serve to cool the injector nozzle. Passage 37 is interconnected with all the valve seat insert passages as described in connection with FIGURE 1; and

therefore the coolant fiow toward the centre of fire plate 31 is as described for FIGURE 1 until the flow reaches passage 37, when the flow is, as shown by arrows in FIGURE 2, through hollow studs 35, 36 and the holes therein to other coolant spaces and exists in the cylinder head (not shown). Fire plate 31 is located in relationto cylinder head 32 by means of locating ring 38.

This embodiment permits speedy removal of fire plate 31 from the cylinder head, as for inspection, repair or replacement; and, equally with the embodiment of FIG- URE 1, achieves the aim of having the coolant medium flow close to the hottest parts and so reduce or eliminate the risk of thermal damage to the cylinder head.

In neither embodiment need the fire plate by flat; it may, for example, have a frusto-conical section, or may be dished. It may have stress and creep-relieving grooves in the combustion space surface, and may also have areaincreasing fins on the coolant surface. It may be, of material other than steel plate, and the fuel injector or spark plug guide tube may be integral with it.

The valve seat inserts may be of material other than steel, and may be faced with a' suitable hard material. Additional removable valve seat inserts of suitable material may be fitted in the seating area of the original inserts described. a

The removable nature of the fire plate allows easy access to the interior of the cylinder head for inspection or the fixing of instruments or indicators such as strain or temperature gauges; and replacement of the fire plate if necessary, may save the replacement of the whole cylinder head.

. 3 Then, referring again to FIGURE 1, certain optional features may be mentioned. Thus, dowels 24, or screws 25 may be provided at the periphery of the fire plate 14 to facilitate its initial location with respect to cylinder head 11 and to secure it to the head during testing for Water tightness (the dowels or screws are not necessary during running of the engine). Alternative locating means may be provided, such as a centre spigot and recess. Radially elongated slots (not shown) in the pe riphery of the fire plate may be provided for each dowel or screw, and a small radial clearance space 26 may be provided in cylinder head 11 around the periphery of the fire plate 14 to allow for thermal expansion; and a small radial clearance space 27 may be provided in liner 15 at the necessary gas and waterproof joint between liner 15 andplate 14. However, the improved cooling arrangement of the invention lessens the risk of appreciable thermal expansion.

It will be understood that the invention can equally wellbe applied to a spark-ignition engine, with the substitution of a spark plug for the fuel injector, or to an engine having any number of valves.

. What I claim is:

1. An overhead-valve, liquid-cooled cylinder head of an internal-combustion engine in which a separate, removable and replaceable fire plate functioning as a combustion space Wall or deck as valve seat inserts which are rigidly secured thereto at both its hot and cool faces and are over substantially thewhole of their peripheries surrounded by interconnecting coolant-fiow passages formed between said hot and cool faces.

2. A cylinder head according to claim 1, in which a coolant flow is arranged from the exterior of an as sociated cylinder or cylinder liner through a plurality of inlet ports at the periphery of the fire plate, at. least one i inlet port being connected with each passage encircling each valve seat insert, the flow being in a generally radially inward direction through said interconnecting passages in the fire plate to a passage surrounding a fuel injector or spark plug, and from thence into the cylinder head.

3. A cylinder head according to claim 1, in which a coolant flow is arranged from an inlet into the cylinder head, and to. a passage surrounding a fuel injector or spark plug, and from thence in a generally radial outward direction through said interconnecting passages in said fire plate, through a plurality of outlet ports at the periphery of the fire plate, at least one outlet port being connected with each passage encircling each valve seat insert, and from thence to the exterior of anassociated cylinder or cylinder liner.

4. A cylinder head according to claim 1, in which the cylinder head and fire plate are cooled by an individual coolant circuit, coolant flowing through said interconnecting passages and a passage surrounding a fuel injector or spark plug, the associated cylinder or cylinder liner being cooled by a separate conventional system.

5. A cylinder head according to claim 2 in which the centre of said fire plate is secured to a remote part of the cylinder head by means of a central guide tube secured therebetween.

6. A cylinder head according to claim 2 in which the centre of said fire plate is secured to a remote part of the cylinder head by means of a plurality of bolts secured therebetween, the coolant flowing from the fire plate to the cylinder head through a hollow stud attached, between the fire plate and each said bolt.

7. A cylinder headof-an internal combustion engine having a separate, removable and replaceable fire plate lying transversely of the cylinder axis to constitute a combustion space wall or deck rigidly secured at its centre only to one end of .a rigid element extending axially of the cylinder and secured at its remote end to a comparatively cool part of the cylinder head in which valve seat inserts passing through said fire plate are rigidly secured to the fire plate at both it hot and cool faces and are surrounded by interconnecting coolantfiow passages within said plate.

8. A cylinder head according to claim 3 in which the center of said fire plate is secured to a remote part of the cylinder head by means of a central guide tube secured therebetween.

9. A cylinder head according to claim 3 in which the center of said fire plate is secured to a remote part of the cylinder head by means of a plurality of bolts secured therebetween, the coolant flowing from the fire plate to the cylinder head through a hollow stud attached between the fire plate and each said bolt.

References Cited by the Examiner UNITED STATES PATENTS 2,736,300 2/56 Flynn l2341.82 X

3,03 5,559 5/62 Brandes.

3,125,082 3/64 Stansfield 123- -4l.82

FOREIGN PATENTS 1,197,576 6/59 France.

RICHARD B. WILKINSON, Primary Examiner. KARL J. ALBRECHT, Examiner,

UNITED STATES PATENT I CERTIFICATE OF CORRECTION I I Patent No. 3,176,666 ,7 April 6, 1965 Herbert A. Whitehead It is hereby certified that/error appears in the above numbered pat.- ent requiring correction and that. the said-Letters Patent should read as corrected below.

In the grant, lineshl to 3, for "Herbert A, Whitehead, of Skellin thorpe, Lincoln,*Englandf' read Herbert A. Whitehead, of Skel ingthorpe, Linc-01.11;... England, assignor to Ruston and Hornsby Limited,"of Af'adfe-rs lljde South, Lincoln, England, a corpora tion of Great Britain, line ..l.2 for "Herbert A'.. Whitehead, his heirs" read RustonandlHornsbyLimited, its. successors in the heading to the.,.printed specification, lines 4 and 5, for "Herbert A. Whitehead, ."Saddlewor-th," Waterloo Lane, 7 Skellingthorpe, Lincoln, England" read Herbert A. Whitehead, Skellingthorpe, Lincoln, England, assignor to Ruston and Hornsby Limited, Waterside South, Lincoln, England, a corporation of' Great Britain Signed and sealed this 16th day of November 1965.

(SEAL) Attest:

ERNEST w. SWIDER I EDWARD J.. BRENNER Attesting Officer 1 Commissioner ofPatents 

1. AN OVERHEAD-VALVE, LIQUID-COOLED CYLINDER HEAD OF AN INTERNAL-COMBUSTION ENGINE IN WHICH A SEPARATE, REMOVABLE AND REPLACEABLE FIRE PLATE FUNCTIONING AS A COMBUSTION SPACE WALL OR DECK AS VALVE SEAT INSERTS WHICH ARE RIGIDLY SECURED THERETO AT BOTH ITS HOT AND COOL FACES AND ARE OVER SUBSTANTIALLY THE WHOLE OF THEIR PERIPHERIES SURROUNDED BY INCONNECTING COOLANT-FLOW PASSAGES FORMED BETWEEN SAID HOT AND COOL FACES. 